Cartridge fireplace firebox

ABSTRACT

In accordance with the present invention an unvented cartridge fireplace firebox that is simple and inexpensive to manufacture, has trapezoidally shaped sidewalls and a back wall that are lined with high gloss ceramic tile, a perforated metal shelf supporting a simulated logset and one or more alcohol fuel cartridges, and a self closing, nearly transparent, single panel wire screen with a latch.

CROSS REFERENCE TO RELATED APPLICATIONS

Not Applicable

FEDERALLY SPONSORED RESEARCH

Not Applicable

SEQUENCE LISTING OR PROGRAM

Not Applicable

BACKGROUND OF THE INVENTION

1. Field of Invention

This invention is for a cartridge fireplace firebox that is simple andinexpensive to manufacture, has trapezoidally shaped sidewalls and abackwall that are lined with high gloss material such as high glossceramic tile, a perforated metal shelf that holds both a simulatedlogset and one or more alcohol fuel cartridges, and a self closing,single panel, nearly transparent wire screen door with a latch.

2. Background of the Invention

In woodburning fireplaces the area where the fire burns, called thefirebox, has historically been made out of brick or similar material.More recently, factory built fireboxes made out of sheetmetal havebecome popular. An example of such a sheetmetal firebox used in awoodburning fireplace is shown by Bailey and Howell in U.S. Pat. No.4,700,687.

Many such fireboxes have wire screens that help prevent unwanted itemsfrom being thrown into the fire and sparks from popping out. Rinker, etal, in U.S. Pat. No. 4,827,902, describes a “pair of heavy gauge metalmesh curtains” (column 7, line 37). Rinker's screens hang on a curtainrod, as shown in Rinker's FIG. 13, and must be manually closed. Suchscreens typically allow most of the light from the fire, frequently 55%to 70%, to pass through.

As gas fireplaces became more numerous sheetmetal fireboxes used withgas burners have also been offered. Two examples of sheetmetal fireboxesused in a gas fireplace are shown by Valters and O'Hearn in U.S. Pat.No. 6,116,232, and Wade, in U.S. Pat. No. 5,901,701.

Similar to woodburning fireplaces, some gas fireplace assemblies havewire screens in front of the fire. Lentz, in U.S. Pat. No. 4,572,156,describes a gas fireplace assembly with manually closed screen doors.Sometimes glass is used instead of screen. Berry, in U.S. Pat. No.4,270,514, describes a gas fireplace assembly with a pair of slidingglass doors. Simington, in U.S. Pat. No. 4,029,076, describes multipleglass doors in a bay window arrangement, and May, in U.S. Pat. No.4,290,409, describes a pair of side hinged glass doors.

Aside from woodburning and gas fireplaces, a third type of fireplace hasbeen sold for a number of years that burns alcohol gel. Many suchfireplaces burn the alcohol gel in two or three round, pint sized,paint-can type cans. The cans are placed behind a freestanding,noncombustible ceramic log. Jensen Metal Products of Racine, Wis. sellssuch fireplaces.

In the Jensen type fireplace both the ceramic log and the round paintcans holding the fuel are placed inside a rectangular sheetmetalfirebox. The rectangular firebox has a non-glossy, painted, finish. Thelog and paint cans sit inside the firebox on a solid, nonperforated,sheetmetal shelf. The firebox has a pair of pull screens on the left andright, hanging on a curtain rod, that have to be pulled together toclose the screen.

A new alcohol system for fueling a fireplace was recently revealed bythis inventor in U.S. patent application Ser. No. 11/099,937. This is acartridge system with two components. One component is a disposable,rectangular, metal cartridge filled with alcohol gel fuel. The cartridgeemploys various measurements and ratios that enable it to self regulatethe width, flutter height, burn time and peak heights of the fire. Theother component is a noncombustible logset that may be a single ceramiccasting but gives the appearance of multiple log pieces. The logset isdesigned to ventilate the sidewalls of the fuel cartridge, which isplaced substantially inside the logset, not behind it. Fire emanatesfrom the top of the cartridge and passes through the top opening of thelogset, thereby giving the appearance of a fire that rises from themiddle of a group of logs, similar to a real wood fire.

Initially, the cartridge system was used by placing it inside brickfireboxes that were part of traditional woodburning fireplaces. Thecartridge system was also used by placing it inside rectangular, Jensenstyle, non-glossy fireboxes. In the latter case the logset and fuelcartridge are placed on the Jensen style, solid, nonperforated metalshelf inside the firebox. The solid shelf did not allow optimumventilation of the sidewalls of the fuel cartridge, but the design ofthe logset compensated for this with an oversized cavity and a back ventthat allowed air circulation.

Despite the fact that the cartridge system could work in both Jensenstyle and traditional brick fireboxes, it soon became clear that thesefireboxes did not take full advantage of the unique features of thecartridge burner system. A better firebox was needed.

For example, although the cartridge system produces a fire that looksextremely realistic, its primary purpose is to create ambiance asopposed to heat. Hence, a firebox designed for the cartridge systemshould highlight the fire's visual effect. This can be accomplished bylining the backwall and/or sidewalls of the firebox with a high glossmaterial, such as high gloss ceramic tile. This enhances theillumination created by the fire. Designs utilizing such tile have beencreated by this inventor and are revealed in design patent applicationsnumbered Ser. Nos. 29/239,297, 29/242,464, 29/242,469, 29/242,468,29/242,516, 29/242,517 and 29/257,237.

The utilitarian aspects of a firebox used with the cartridge burnersystem are also different from existing fireboxes. For example, thesidewalls of the cartridge require significant ventilation so that thecartridge does not overheat. This invention increases the amount of airflow around the cartridge by placing it, and the logset surrounding it,on a perforated metal shelf which permits more air movement around thecartridge's sidewalls.

Other utilitarian aspects of a firebox used with the cartridge burnersystem are also relevant. For example, whereas the manually adjustedpull screens used on other fireboxes only allow about 55% to 70% of thelight from the fire to pass through the screen, in a cartridge systemmuch more light may be allowed to pass through the screen. This isbecause the cartridge system does not produce popping sparks and embers.Therefore, larger openings between the wires can be employed on thescreen. In fact, a nearly transparent wire screen, such that allowsabout 80%-90% of the light from the fire to pass through, may be used.

In addition, the cartridge system eliminates the need for multiplescreens hanging on a rod or multiple glass doors. Instead, a single, tophinged frame can be used which holds the screen. Because it is tophinged, the screen defaults to the closed position when the consumerlets go of it. Hence, gravity closes this screen automatically, withoutmanual adjustments. The screen also has a latch so it can be secured inthe closed position.

Other improvements over existing fireboxes are also accomplished by theinvention disclosed here, such as lessening the cost of the firebox andmaking it simpler to manufacture.

For example, as explained by Wade in U.S. Pat. No. 5,901,701, manysheetmetal fireboxes can be expensive to manufacture because theyfrequently require layers of steel welded to each other and separated byair gaps. This “box within a box” layout is how many fireboxes containand/or dissipate the heat generated by the fire. As Wade explains, thisis required because traditional fireplaces can generate as much as40,000 BTU's of heat.

The cartridge system, however, can produce a visually pleasing fire thatonly generates about 5,000 BTU's of heat. Because much less heat isproduced, the cartridge system does not require a complex “box within abox” design. For these and other reasons a firebox that took advantageof the unique characteristics of the cartridge burner system wasdesirable. The present invention accomplishes this result.

DISADVANTAGES COMMON TO THE PRIOR ART

The applicant is unaware of any fireplace firebox that takes advantageof the cartridge burner system described by this inventor in U.S. patentapplication Ser. No. 11/099,937.

As discussed by Wade in U.S. Pat. No. 5,901,701, and as illustrated bythe patents cited earlier, traditional firebox designs for wood or gasfireplaces require chimneys, “box in a box” designs or componentsrequired to dissipate high levels of heat, sometimes as high as 40,000BTU's. This makes their construction more complicated and expensive thanthe present invention. In addition, none of the previously cited patentsdescribe a firebox that has trapezoidally shaped sidewalls and abackwall that are lined with a high gloss material such as high glossceramic tile, a perforated metal shelf that holds a simulated logsetsurrounding a fuel cartridge, and a self closing, nearly transparent,single panel wire screen door with a latch.

Although several non-traditional firebox type inventions have beendisclosed that use multiple round cans of alcohol fuel as opposed towood or gas, none of these inventions have the features describedherein. For example, Facchina, in U.S. Pat. No. 5,794,610, discloses afireplace that burns fuel in multiple round cans which does not includea nearly transparent, self closing, single panel, screen with a latch.Nor does Facchina's invention contain sidewalls and a backwall linedwith a high gloss material such as high gloss ceramic tile, or aperforated shelf supporting a noncombustible logset and fuel cartridgesitting thereon.

Similar to Facchina, Fischer, in U.S. Pat. No. 4,838,781, also disclosesa fireplace apparatus that uses multiple round cans of fuel. Fisher'sinvention, however, does not disclose trapezoidally shaped sidewalls ora backwall that are lined with a high gloss material such as high glossceramic tile, a self closing, nearly transparent, single panel screenwith a latch, nor a perforated shelf to support a noncombustible logsetand fuel cartridge sitting thereon

Similar to Facchina and Fischer, Myers, in U.S. Pat. Nos. 4,573,905 and4,890,600, discloses fireplace systems that also burn fuel in multipleround cans. Myers' inventions do not include a self closing, nearlytransparent, single panel, latched screen, nor a perforated shelf thatholds a logset as shown here, nor a backwall and trapezoidally shapedsidewalls that increase illumination through the use of a lining made ofhigh gloss material. Instead, both of Myers' patents increaseillumination by using supplemental electric lights.

BACKGROUND OF INVENTION—OBJECTS AND ADVANTAGES

The objects and advantages of the invention described herein are toprovide a cartridge fireplace firebox that:

-   -   (a) is simple and inexpensive to manufacture,    -   (b) enhances the illumination provided by the fire by placing a        high gloss material, such as high gloss ceramic tile, on the        back wall and both trapezoidally shaped side walls of the        firebox,    -   (c) allows 80%-90% or more of the illumination to be visible        through the screen in front of the firebox by employing a screen        that has a large open area, such as an 80%-90% open area.    -   (d) uses a single screen that is self closing because it        defaults to the closed position when you let go of it,    -   (e) has a perforated metal shelf that may hold both a simulated        logset and one or more alcohol fuel cartridges,    -   (f) has a perforated metal shelf that enhances the air        circulation around the sidewalls of the fuel cartridge,

SUMMARY

In accordance with the present invention there is provided a cartridgefireplace firebox that is simple and inexpensive to manufacture, withtrapezoidally shaped sidewalls and a backwall that are lined with a highgloss ceramic material such as high gloss ceramic tile, a perforatedmetal shelf that holds both a simulated logset and one or more alcoholfuel cartridges, and a self closing, single panel, nearly transparentwire door with a latch.

DRAWINGS—FIGURES

FIG. 1 shows the invention with the self closing screen in a partiallyraised position.

FIG. 2 shows the interior components of the firebox, including theperforated metal shelf, the high gloss material, such as high glossceramic tiles, on the side walls and back wall, and the heat absorber atthe top.

FIG. 3, which is not part of the invention and is shown for illustrativepurposes only, shows a noncombustible logset and a fuel cartridge thatsits therein.

FIG. 4 shows the invention with Line 4 drawn as a reference point forthe cross sectional view shown in FIG. 5.

FIG. 5 is a cross sectional view of the invention with a logset andcartridge therein, and a fire coming from the cartridge.

FIG. 6 shows a representative hinge mechanism.

FIG. 7 shows a representative latch mechanism.

FIG. 8 shows an alternative embodiment of the invention, with a glasspanel in place of the self closing screen.

DRAWINGS—REFERENCE NUMERALS

-   -   1 Invention    -   12 Bottom wall    -   14 Lower face    -   16 Lower vent    -   18 Right face    -   18A Left face    -   20 Right wall    -   22 Back wall    -   24 Top wall    -   26 Left wall    -   28 Top face    -   30 Top vent    -   32 Frame    -   34 Self closing screen    -   34A Tempered glass    -   36 Latch    -   38 Perforated metal shelf    -   40 Support rods    -   42 Metal heat absorber plate    -   44 High gloss material    -   46 Fuel cartridge    -   48 Logset    -   50 Cavity    -   52 Fire    -   54 Hinge    -   56 Catch

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENT

The presently preferred embodiment of the invention is illustrated inthe figures. FIG. 1 shows the trapezoidally shaped firebox formed bylight weight sheet steel, such as 18 or 20 gauge steel, comprising of abottom wall 12, right wall 20, left wall 26, top wall 24 and back wall22. The front of the invention also has a right face 18, left face 18A,lower face 14 and top face 28. The top face 28 has top vents 30 and thelower face 14 has lower vents 16. The front of the invention has a selfclosing screen 34 held in the frame 32.

The frame 32 is held in place by a top mounted hinge 54. The top mountedhinge 34 can take different forms, such as a pivot hinge or a continuoushinge, as is well known to those practiced in the art of making hinges.The continuous hinge shown in FIGS. 5 and 6 connects the top of theframe 32 to the top face 28. If a pivot hinge is used it will connectthe top of the left and right sides of the frame 32 to the top of theright face 18 and the top of the left face 18A.

Because the self closing screen 34 is hinged at the top it will defaultto the closed position. The self closing screen may also be latched inthe closed position with the latch 36. The latch 36 can take differentforms, such as a cam latch, swinging bar latch, slide bolt latch, etc.,as is well known to those practiced in the art of making latches. In theexample shown in FIGS. 1 and 7, the cam latch 36 is mounted on thebottom of frame 32 and engages the catch 56 mounted on the lower face14.

FIG. 2 shows the high gloss material 44, such as high gloss ceramictile, that lines the side walls 20 and 26, and the back wall 22. FIG. 2also shows the perforated metal shelf 38 sitting above the bottom wall12, and the metal heat absorber plate 42 held in place by the supportrods 40. The support rods 40 may be 0.25″ diameter steel, to allowsubstantial air movement around the rods and over the heat absorberplate 42.

During use, the logset 48 and the fuel cartridge 46, which are not partof this invention but are shown for illustrative purposes, sit on theperforated metal shelf 38, which is positioned above the bottom wall 12.As shown in FIG. 5, the fuel cartridge 46 sits in the logset cavity 50.When the cartridge is lit a fire 52 is produced. The illumination fromthe fire is enhanced by the high gloss material 44, thereby increasingthe amount of light that leaves the firebox 1.

The vast majority of the light of the fire passes through the selfclosing screen 34. The self closing screen 34 may be a “two mesh”screen, meaning it has two strands of wire per lineal inch, resulting inopenings that are almost 0.5″ square. The wire used for the self closingscreen 9 may be relatively light, such as 0.028″ diameter wire, orheavier wire, such as 0.047″ diameter.

The transparency level of the self closing screen 34 is much higher thanthat of many other fireplace screens. According to the Universal WireCompany, of Morrisville, Pa., which makes fireplace screen, such screensare commonly made out of mesh with eight openings per lineal inch, using0.028″ diameter wire. According to the charts published by ClevelandWire Cloth, of Cleveland, Ohio, another manufacturer of fireplacescreen, a mesh made out of 0.028″ diameter wire that has nine strands ofwire per lineal inch (resulting in eight openings per lineal inch) hasan open area of 55.95%. Using the same wire, mesh with eight strands perinch results in 60.02% open area, and mesh with only six strands perinch has 69.6% open area.

Because the current invention is made to be used with a cartridge burnersystem that does not produce any sparks, and may use a 2 mesh selfclosing screen 34 made with 0.28″ wire, the percentage of open area onthe self closing screen 34 is 89.11%, meaning over 89% of the light fromthe fire passes through. Even if the self closing screen 34 is made withheavier wire, such as 0.047″ diameter wire, its transparency level isstill about 82%. Hence, this firebox 1 allows much more of the fire tobe seen through the self closing screen 34 than many other fireboxeswhose screens do not close automatically.

Ambient air used for combustion enters the firebox through the selfclosing screen 34 or the lower vents 16. A substantial portion of theheat produced by the fire 52 will initially be absorbed by the metalheat absorber plate 42. Heated air exits the firebox 1 through the selfclosing screen 34 and through the top vents 30.

Alternative Embodiments

As an alternative embodiment the self closing screen 9 may be replacedwith tempered glass 34A, also top hinged, so that it too defaults to theclosed position.

1. An alcohol fireplace firebox comprising a top wall, bottom wall, twoside walls and a back wall, which side walls and back wall are linedwith a high gloss material such as high gloss ceramic tile, whichsidewalls are trapezoidal in shape and where the said firebox has a selfclosing screen.
 2. An alcohol fireplace firebox according to claim 1wherein the screen has a latch.
 3. An alcohol fireplace fireboxaccording to claim 2 wherein the screen has over 80% open area.
 4. Analcohol fireplace firebox according to claim 1 wherein the firebox has aperforated metal shelf to hold a logset and an alcohol fuel source. 5.An alcohol fireplace firebox according to claim 2 wherein the fireboxhas a perforated metal shelf to hold a logset and an alcohol fuelsource.
 6. An alcohol fireplace firebox according to claim 3 wherein thefirebox has a perforated metal shelf to hold a logset and an alcoholfuel source.
 7. An alcohol fireplace firebox comprising a top wall,bottom wall, two side walls and a back wall, which side walls and backwall are lined with a high gloss material such as high gloss ceramictile, which sidewalls are trapezoidal in shape and where the saidfirebox has a self closing tempered glass door.
 8. An alcohol fireplacefirebox according to claim 7 wherein the tempered glass door has alatch.
 9. An alcohol fireplace firebox according to claim 7 wherein thefirebox has a perforated metal shelf to hold a logset and an alcoholfuel source.
 10. An alcohol fireplace firebox according to claim 8wherein the firebox has a perforated metal shelf to hold a logset and analcohol fuel source.
 11. An alcohol fireplace firebox according to claim9 wherein the tempered glass door has a latch.
 12. An alcohol fireplacefirebox according to claim 10 wherein the tempered glass door has alatch.